Word or text processing systems having interactive display terminals permitting an operator to extensively edit and format alphanumeric data which is, in turn, printed out on an associated printer have been in ever increasing demand in the office products and systems field. Since a great many letters, articles to be published and books require some graphic material to be formatted into documents along with the alphanumeric text, there has been a need for improved editing capability with respect to graphics on word processor displays. There has also been a need to provide associated printing means which efficiently, inexpensively and rapidly print documents containing such integrated alphanumeric and graphics data.
Most conventional word processing systems with interactive display terminals generally operate the display terminal as a character generation or "character box" display. In such a display, an encoded representation of each of a font of characters is stored in a character generator memory, and as each character is to appear on the display during each display refresh cycle, the character generator memory is addressed and the coded representation of that particular character is taken from the memory and displayed in a particular and designated "character box" on the display. Similarly, most printers associated with existing word processing systems print their characters on a character by character basis. Such an association of a display terminal and printer is obviously a practical one since the data representation of a particular character in the display or editing level data stream may with minimum modification be utilized in the print level data stream to activate that particular character on the printer. Accordingly, in order to achieve desirable graphics capabilities in a word processing system, the graphics should be implementable in a character generation mode for display and for display purposes and be printable on a character by character basis on the printer.
The following prior art is representative of the handling of graphics on various displays.
U.S. Pat. No. 4,246,578, I. Kawasaki et al, Pattern Generation Display System, issued Jan. 20, 1981. This patent discloses a display on which both graphics and alphanumeric data may be shown. It does not use a character generator for the alphanumerics. Rather, all displayed material is generated through some sort of an All Points Addressable system.
U.S. Pat. No. 4,272,767, R. H. Lacy, Display System for Displaying Information in the Form of a Horizontally Oriented Curve on a Raster-Type CRT, issued June 9, 1981. In this display terminal for showing both alphanumeric and graphic material, the alphanumerics are generated through character generation but the graphics or curves appear to be generated by some other means involving vectors.
U.S. Pat. No. 4,338,599, S. Leininger, Apparatus for Alpha-Numeric/Graphic Display, issued July 6, 1982 covers a display for graphic and alphanumeric information. While the alphanumeric information appears to be displayed through some sort of character generation, the graphic data is displayed through a different scheme which does not appear to utilize character generation.
U.S. Pat. No. 4,283,723, R. H. Bickley et al, Apparatus and Method for Providing Digital and/or Bar Graph Displays of Measured Quantities, issued Aug. 11, 1981 appears to relate to a very specialized display forming both characters and simple bar graphs through a character generation method. However, the teaching is quite specialized and appears to be in no way suggestive of or related to the production of printed documents and particularly a word processing system controlling the printing of documents or the formation of graphics on such documents.